1. Field of the Invention
The present invention relates to toughening ring-opened polymers and copolymers of dicyclopentadiene (poly DCPD) by the use of dispersed polymeric particles having a core and shell structure, and toughened polymers and copolymers of dicyclopentadiene comprising such polymeric particles.
The present invention also relates to imparting improved resistance to oxidation to ring-opened polymers and copolymers of dicyclopentadiene by the use of dispersed polymeric particles, preferably having a core and shell structure, and polymers and copolymers of dicyclopentadiene comprising such polymeric particles having improved resistance to oxidation.
The present invention also relates to imparting greater retention of mechanical properties upon thermal aging to ring-opened polymers and copolymers of dicyclopentadiene by the use of dispersed polymeric particles having a core and shell structure, and polymers and copolymers of dicyclopentadiene comprising such polymeric particles having greater retention of mechanical properties upon thermal aging.
The present invention relates to the production of improved metathesis polymerized polymer comprising such dispersed polymer particles, and the resultant improved metathesis polymerized polymer.
The metathesis polymerized polymer is made by ring-opening polymerization of metathesis polymerizable monomers, such as dicyclopentadiene and other strained ring polycyclic olefins. Specifically, the present invention relates to the use of a particle, preferably having a core and shell structure where the core comprises polybutadiene and the shell comprises crosslinked, polymethylmethacrylate to produce a crosslinked, thermoset dicyclopentadiene polymer having a high notched izod (NI) impact.
2. Discussion of Background Information
Polydicyclopentadiene (poly DCPD) prepared by ring-opening metathesis retains both of the double bonds present in the monomer. The double bonds are present either in the polymer backbone, in the crosslinks or branches between chains, or in unopened cyclopentene rings pendant to the polymer chains. These double bonds all provide sites for oxidation of the polymer chain. Antioxidants can be added which provide substantial increases in the stability of the polymer as measured by increases in retention of notched izod, Gardner, and plate impact strengths, and tensile elongation.
Polydicyclopentadiene can be toughened by the addition of an elastomer which is dissolved in the starting monomer, and subsequently phase separated during the polymerization to form a dispersed elastomer phase, for example, as disclosed in U.S. Pat. No. 4,400,340, Klosiewicz, and its related U.S. Pat. Nos. 4,436,858 4,469,809; 4,485,208; and 4,657,981. U.S. Pat. No. 4,400,340, Klosiewicz, also describes the preparation of high impact resistant thermoset polymer of dicyclopentadiene (DCPD) by ring-opening polymerization of dicyclopentadiene in the presence of a metathesis catalyst.
It is also known to toughen thermoset polymers by the addition of rubber particles, such as in U.S. Pat. Nos. 4,783,506, Gawin, 4,863,787, Gawin, 4,977,218, Gardner, and 4,977,215, Gardner.
In contrast to the rubber particles, or balls, which are generally formed in toughening other thermosets such as epoxies, or thermoplastics, such as polystyrene, the morphology of the rubber phase in polydicyclopentadiene appears as a very diffuse, strand-like semi-continuous phase in TEM photomicrographs.
U.S. Pat. Nos. 4,689,380, Nahm, and 4,703,098, Matlack, relate to copolymerizing dicyclopentadiene (DCPD) with other strained ring polycyclic cycloolefins such as other cyclopentadiene oligomers so as to increase the glass transition temperature of the resultant polymer.
U.S. Pat. No. 4,481,344, Newburg, uses a halogen-containing hydrocarbyl additive that contains at least one trihalogen-substituted carbon atom or at least one activated halogen atom is added to at least one of the reactant streams.
U.S. Pat. Nos. 4,957,974 and 4,997,884, Ilenda et al., disclose polyolefins with improved impact strength by the addition of core-shell polymers compatibilized with the polyolefin matrix by the addition of a polyolefin-acrylic graft copolymer.
U.S. Pat. No. 5,047,474, Rabinovich et al., disclose impact modifier compositions consisting of a mixture of acrylic core-shell polymer and MBS core-shell polymer.
U.S. Pat. No. 5,094,806, Laughner, discloses examples of elastomeric impact modifiers for fluorinated polyolefins.
European Patent Publication No. 0 392 348, BASF, relates to toughened, thermosetting structural materials achieved by incorporating particles having a size within the range of 2 to 35 .mu.m of differently soluble thermoplastics into heat curable epoxy resin systems.